[Castor-users] about counts outside the phantom volume on reconstructed image

[STUTE Simon]

Hi Ashok,


This is usually normal to have leftover signal outside the object, but it seems that you have more than normal.


How many iterations did you run ?


>From your image, it seems that you are using a geometry without cylindrical symmetry.

If so, it may be possible that some regions of your field-of-view are not "seen" from a number of different angles that is enough to fully resolve these regions.


Hope this helps.


Best

Simon


________________________________
De : Castor-users <castor-users-bounces at lists.castor-project.org> de la part de Tiwari, Ashok <ashok-tiwari at uiowa.edu>
Envoyé : dimanche 26 juillet 2020 16:13
À : castor-users at lists.castor-project.org
Objet : [Castor-users] about counts outside the phantom volume on reconstructed image

Dear CASToR users and developers,

I've simulated a uniform phantom in GATE and exported the GATE data to CASToR for image reconstruction. During reconstruction, I've chosen only the true events and ran a reconstruction, with and without attenuation correction. Then I visualize the image using ImageJ (see attached), but I do not understand why counts are appearing outside the phantom volume. Could anyone help me understand why this is happening here? Has anyone seen this before? Is it due to noise and/or scattering outside the phantom?

Thank you for your help in advance.


Regards,

Ashok


---------------------
Ashok Tiwari
Ph.D. Candidate
Department of Radiology & Physics
University of Iowa Hospitals and Clinics
Office: P158, MRF
200 Hawkins Drive
Iowa City, IA 52242
ashok-tiwari at uiowa.edu

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